Not too surprisingly, Sprint's "4G" phone buildout is largely going to ride on the back of their spun-off Clearwire mobile WiMax venture. Sprint will essentially operate as an MVNO on the Clearwire network, offering a lot of gear that provides CDMA/EDGE, Mobile WiMax and Wi-Fi connectivity. Of course that means the Sprint next-gen broadband markets are likely going to mirror Clearwire's existing footprint, with networks commercially available in Atlanta, Las Vegas (which officially launched today), Portland and Baltimore.

With that in mind, it wasn't too surprising to see Sprint announce this morning that their faster 4G service will first be made available in Las Vegas, Portland and Atlanta starting in August after it first popped up in Baltimore last fall. According to Sprint, Charlotte, Chicago, Dallas, Ft. Worth, Honolulu, Philadelphia and Seattle will also see service this year. A few smaller markets you may have heard of will come online in 2010, like Boston, New York and DC.

While Sprint's EVDO service currently has a 5GB monthly limit, the company website insists the new service will be "unlimited." That word has been abused enough in this industry for users to be skeptical until they see more serious deployment. As for speed, Sprint says that the service will "deliver peak downlink speeds of more than 10 Mbps and average downlink speeds of 3-6 Mbps." Last December Sprint announced the availability of the U300 modem, which provides users with data access to both their EVDO and Mobile WiMax networks.

With Comcast also planning to offer wireless broadband powered by Clear, there's going to be an awful lot of re-branding, cross-purpose marketing and co-habitation going on in next few months. That could wind up confusing consumers -- and will seriously test the new Clearwire network. All of this hinges on how quickly Clearwire can get things deployed -- the operator is promising deployment to 80 markets over the next eighteen months.